Stoker structure



i 150ml May W39- R. E.I SRsSLER STOKER STRUCTURE Filed 'r llllllllrlllllanllfldfl virili/ll NOV. 7, 1936 Patented May 3o, 1939 UNITED STATES v 2,160,641 s'romsa s'raUo'rURE f of Illinois Application November 7, 1936, Serial No. 109,688

2 Claims.

In such stokers as heretofore made, under certain operating conditions, the air pressure in the burner, being higher than that in the hopper, causes air to travel back through the fuel conduit to the hopper. When smoke is present in the burner, as when gas is released from the fuel being supplied, due to the heat* generated by the burning fuel, it is carried back to the hopper and discharged out through the same. Such a condition is known as smoke back. It is apparent that this condition is objectionable.

One of the objects of the present invention is to provide a'stoker structure which eliminates smoke back in a simple and expeditious man- A ner.

Another object of the invention is to provide a stoker structure which includes means to eliminate smoke back, which means shall add substantiallynothing to the cost of the structure, and which shall have no parts requiring cleanin or maintenance.

. A further object of lthe invention is to provide a stoker` struct-ure embodying therein means whereby air pressure in the burner and in a certain part of the fuel conduit leading thereto,.is equalized so that smoke cannot follow along the conduit to vthe hopper for discharge.

The above mentioned object of the invention, as well as others, together with the advantages thereof, will 'more fully appear as I proceed with myspecification.

In the drawing: c

Fig. 1 is a view partly inside elevationV and partly` in longitudinal vertical section' of a Stoker structure embodying the preferred form of the invention.

Fig. 2 is a transverse vertical sectional view through a part of the improved stoker structure 50 as taken on the line 2-2 of Fig. 1. Fig. .3 isanother'transver'se.. vertical sectional viewthrough a. part of the improved s'toker structurel 'as taken onthe line 3--3 of Fig. 1.

Fig. 4 is a perspective view of 'the' burner proper 55 and a part of its fuel inlet-tube. of the improvedA stoker structure and -which will be more fully referred to later.

Fig. 5 is a transverse vertical sectional view. through a modified form of Stoker structure embodying the invention and'which will be more 6 fully referred to later.

V Referringnow in detail to that embodiment of the invention Villustrated in the accompanying drawing: 5 indicates as a whole the fuel holding hopper of the Stoker and 6 indicates a fuel conl0 d-uit, extending along one side or the bottom of the hopper so that the same communicates with said conduit.

1' indicates the burner or retort of the stoker, the side and end walls of which flare upwardly 15 and outwardly from the rounded bottom 8 arranged axially in line with the fuel conduit 6. On the top of the burner are the tuyre blocks 9 with whichv the dead plates I0 cooperate in wel] known manner. The burner is of such shape that 20 it may be tightly connected to the end of the feed conduit 6. As shown herein, a tubular extension II is provided at one end for that purpose. On the other end wall of the burner is another and shorter tubular extension I2 with a closed end. 25

Preferably, the burner 1 and its tubular extensions II and I2 are made as an integral casting.' Itis provided with feet I3 for engagement upon a suitable support such as the floor I4. 'I'he tubular extension II is provided at a point along 3'0" its top with an upright tubular.'air inlet I5 which opens into the air box or chamber of the burner, as will be later described. -Along one side the extension I I is a cored-out channel I 6, one end of which turns upwardly to merge into the inlet 35 I5.v This channel tapers in radial-depth toward its other end, where it dies out into the rounded bottom of the burner. It is apparent that by the provision ofthe channel described, the crosssectional area of the tubular extension is increased 40 in the transverse plane of the inlet and that this.

-area decreases rearwardly towardthe rounded bot-tom 8 of the burner or retort. y

I1 indicates as a whole, the feeding-means `for the fuel which extendsfrom a point rearward of 45 the hopper'through the conduitv 8 andexten'sionv I I into the burner or retort. 'I'he feeding means as herein shown constitutes a screw of,a diameter properly fitting said 4conduit 6 land extension II. Said screw includes an axial shaft I8. upon which are provided flights` I 9 .for movingth'e f uel to the The shaft. I8 extends` into and operatively connected, to a suitable .drive 'mechanism'contained in a box 2| located forwardlyl of the hop- 55 per' 5. The drive mechanism in said box is driven by means of a motor 22 engaged upon'the box. Air to support combustion is provided by a suitably driven blower 23 and leading off therefrom is an air duct 24.

As shown in Fig. 1, the burner proper is 1ocated in a furnace body or casing indicated as a whole as at 25. The body or casing which also engages upon the i'loor I4,l includes the usual upright walls, only the front and rear walls 26-21 thereof appearing in Fig. l. The outer marginal parts of the dead plates I engage with the said upright walls and coact therewith and with the floor I4 in forming an air box or chamber 28. By reason of thetuyre block section 9 of the burner, the interior of the burner is incommunication with the air box or chamber 28.

In the front wall 26 of the furnace above the dead plate IU is an opening 29 closed by a'conventional door 29a. This opening gives access to the burner in lighting the same at the start of a burning operation and it also provides the means for inspecting the fire and removing clinkers, etc.

Of course the front wall 26 has a suitable opening near the bottom for the passage of the burner tube extension II therethrough. Also, said wall has an opening therein, to which the associated end of the air duct 24 is connected to deliver air into the chamber or air box 28.

In the operation of the burner, the fuel is moved from the hopper to the burner, through the conduit 6 by means of the flights I9 of the screw, which rotates in the direction of the arrow (see Fig. 2), when the channelv I6 is on the right hand side of the tube extension II When the channel I6 is on the left hand side of the extension, the screw is rotated in the opposite direction.

Withthe blower 23 in operation, the duct 24 delivers air into the air box or chamber 28 and through the tuyre section into the burner to support combustion.` Of course, with this air so delivered into the burner, it is apparent that a higher pressure exists therein, than exists in the hopper. However, with the construction described, part of the air in the box or chamber 28, enters the inlet tube section II through the inlet I so that the pressure in the burner and inthe tube section II is substantially equalized. Thus, in the combustion of fresh fuel, when the volatiles thereof are released for initial burning, the smoke thereby produced cannot'travel back through the fuel conduit to the hopper because of the equalized pressures existing in the burner and in that part of the fuel tube between the burner or retort and the air inlet I5.

By reason ofthe channel arrangement in the tube section II as described, and with the screw flight I9 turning toward the right, the fuel in said section is caused to fall away from the air inlet opening I5. Thus, at no time can the fel pile or work up through the opening I5 to spill into the air box or chamber or to plug up said opening. The fuel which has fallen away from the air inlet I5 is directed by the channel I6 back into the tube 5.5 extension for delivery into the burner.

Byereason ofthe structure described, smoke cannot pass back through the fuel conduit to they hopper for a leakage or discharge out through the same. Thus the condition known as smoke bac is eliminated.

In Fig. 5 is illustrated a structure wherein the air chamber is made as a wind box 30 to surround the associated part of the fuel conduit 3l. On the topwall of the box is a tubular extension 32 which coacts with a wall extension 33 on the conduit to form a passage 34 that aords communication between the wind box and the fuel conduit to equalize the pressure therein. The top of the wind box extension 32 is closed by a movable cap 35. Of course, the conduit 3| has a, channel 36 along one side for the purpose mentioned in connection with the channel I6.

It is apparent that the structure eliminating said objectional condition has no'parts that require cleaning or maintenance, and that said structure adds substantially nothing to the cost of producing the stoker.

While in describing the invention, I have referred in detail to the form, arrangement and construction of the various parts thereof, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

I claim as my invention:

1. In a stoker structure, an article of manufacture comprising a feed tube section, means on one side of said section providing an upwardly opening tubular projection for the entrance of air thereinto, means providing a longitudinally extending internal channel along another side of the conduit section spaced arcuately from the rst mentioned side, one end of said channel extending around a part of said tube section and communicating with said tubular projection for the' passage of air, said channel being of the greatest cross sectional area at said end and diminishing in cross sectional area toward its other end, and rotating feeding means within the tube section, said rotating means having its upper side rotating toward said channel.

2. In a stoker structure, as an article cf manufacture, means providing a fuel conduit and a wind box surrounding a part of the conduit, means providingl an upstanding tubular air inlet projection on the top of a part of said conduit for communication with said wind box, means providing a longitudinally extending internal channel in one side of said conduit and having one end exteding around a part of said conduit and communicating with said projection, said channel being of the greatest cross sectional area at said end and diminishing in cross sectional area toward the other end, and means on said -wind box providing access to said tubular projection, and a rotating feed screw in said conduit, the upper part of said feed screw rotating toward the channel.

- ROBERT E. BRESSLER. 

